Application Specific Integrated Circuits (ASIC) Information

Application-specific integrated circuits (ASIC) are microchips developed and produced to satisfy a specific application requirement.

Despite the high cost of ASIC design, they can be advantageously tailor-made to exact product requirements and reduce the need for additional components. ASICs are therefore economical for high-volume production.

Applications and Design

Because they are designed for a very specific purpose, ASICs are first specified by their intended application. This specification is typically more granular than a general industry designation (automotive, medical, etc.), as the chips are often produced to accomplish a narrow task within a specific industry.

Many ASICs are designed using a standard-cell approach, in which basic logic functions from a cell library or IP core are combined to accomplish the chip's primary function. CAD designers must map not only the logic design for the chip, but the physical component design as well.

Most ASIC uses can be accomplished using multiple components or a field-programmable gate array (FPGA). FPGAs are similar to ASICs in that they are application-specific, but differ in that they are reprogrammable and less efficient. FPGAs are typically used in low-volume production, for research and development operations, and to economically test ASIC designs before implementation.

The hour-long video below provides an excellent overview of the differences between ASICs and FPGAs.

In light of the chip differences described above, the table below illustrates some advantages and disadvantages of using application-specific integrated circuits.

Advantages

Small size

Low power consumption and high speed

Minimal routing issues

No timing issues due to single-chip design

No post-production configuration required

Disadvantages

Inflexible

Higher cost, especially on low-volume products

Increased time-to-market

Types

ASICs can be divided into multiple types according to the degree of design and development involved.

Type

Description

Advantages

Disadvantages

Full-custom

All photo-lithographic layers are custom-designed; often used for mobile processors and sensor ICs

Reduced area and footprint; low cost per device; ability to integrate existing components into chip

Increased manufacturing time; high up-front cost; complex CAD

Standard-cell-based

Built from functional blocks with known electrical characteristics

Highly flexible; low risk; short manufacturing time

Moderately high cost per device and up-front costs

Gate-array-based

Constructed of interconnected logic cells; also known as “semi-custom”

Low up-front cost; short production cycles

Often high cost per device; relatively inefficient

The image below shows the functional difference between a gate-array and standard-cell ASIC. A notable difference is that the up-front costs of producing a gate-array chip can be shared by multiple customers, as these chips use a basic shared platform. In contrast, standard-cell ASICs use less space and are more efficient, but are totally unique to an application and therefore more expensive to produce.

Field-programmable gate arrays (FPGAs) have a different architecture than SPLDs and CPLDs, and typically offer higher capacities. FPGAs are also known as logic cell arrays (LCA) and programmable ASIC (pASIC).